Comprehensive study of Ga activation in Si, SiGe and Ge with 5 × 10⁻¹⁰Ω·cm²contact resistivity achieved on Ga doped Ge using nanosecond laser activation

Abstract

Ga diffusion and activation in Si, SWGe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sub> and Ge are studied comprehensively. Optimal Ga activation conditions for Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4</sub> Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sub> and Ge feature a low thermal budget: Ga is highly activated at 400°C in Ge and at 500°C in SWGe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sub> using a 1min rapid thermal annealing (RTA); the activation is further boosted using short-duration high-temperature nanosecond laser activation (NLA). A low Ti/p-Ge contact resistivity (pc) of 1.2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> Q-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is approached using Ga doping and 400°C RTA activation, while a record-low pc for p-Ge down to 5×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> Qcm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is achieved using NLA for Ga activation.